It often becomes necessary in the surgical arts to reapply soft tissue (e.g., ligaments, muscle, cartilage and tendons) to the bone structure of a patient so as to cause adherence and growth of the soft tissue to the bone. Thus, for example, soft tissue torn loose from the underlying bone in an injury is so rejoined. In other operations, soft tissue is surgically separated from the underlying bone so that it can be shortened or moved, and is then rejoined to the bone. An example of such an operation is the well known surgical procedure in which the patellar tendon is translated medially to inhibit lateral subluxation of the patella in the femoral groove.
Surgical staples provided with soft tissue retaining teeth on the underside of the transverse bridge member are known. An example of such a staple is the Richards Fixation Staple (Richards Manufacturing Co., Inc.; Memphis, Tenn.). Since the orthopedic surgeon will usually have need for other staples not having such soft tissue retaining teeth, he will have to maintain a double inventory of staples. Additionally, depending on the particular problem with which he is faced, the surgeon may wish to employ a soft tissue retention capability in combination with the particular characteristics of a certain type of bone staple (e.g., compression staple, non-compression staple, barbed staple, non-barbed staple, etc.). Such freedom of combination is not provided by commercial products in which the soft tissue retaining teeth are integral with and not separable from the remainder of the staple.
U.S. Pat. No. 3,855,638 discloses a staple for the rejoining of soft tissue to bone wherein a portion of the staple is provided with a porous coating capable of sustaining soft tissue ingrowth. This coating, formed by sintering metal particles onto the surface of the staple, provides some soft tissue retention by friction immediately after implantation but does not pierce the soft tissue. Thus, the possibility that the soft tissue may slip relative to the staple and bone before substantial soft tissue ingrowth occurs is not precluded.